1. Field of the Invention
This invention is concerned with the construction of a powertrain for an automobile of a type having an engine and a transmission which are transversely disposed and arranged one behind the other.
2. Description of Related Art
Typically, in automotive vehicles such as four wheel drive vehicles and front engine-front drive (FF) vehicles, the design of a powertrain primarily depends upon whether an engine and a transmission are mounted transversely or lengthwise in an engine room of the vehicle body. In a transversely mounted powertrain arrangement, if both an engine and a transmission are aligned, i.e., mounted in line, the overall length of the entire powertrain becomes large and the powertrain is not practical. Because of this, some powertrains have a formation in which a transmission is positioned behind an engine and a power transmitting means, such as a gear train and a chain, is used to operationally couple the engine and the transmission to each other. Such a powertrain has already been developed and is practically in use. Japanese patent application No. 63-146,128, entitled "Power Transmitting Apparatus," filed on Jun. 14, 1988 and laid open to the public as Japanese Unexamined Patent Publication No. 1-316560 on Dec. 12, 1990, discloses one such powertrain.
In what is referred to as a "parallel transverse" powertrain formation, a transmission is located behind an engine in a lengthwise direction of the vehicle body, and a steering rack or a cross member typically occupies a position behind the transmission. The vertical positional relationship between the steering rack or the cross member and a power output component of a propeller shaft, through which a driving force is transmitted to rear wheels from the transmission, importantly influences the ability to make the propeller shaft straight as well as how easy it is to assemble the powertrain to the automotive vehicle. In other words, when the power output component of the propeller shaft is disposed below the steering linkage or the cross member, the power output component is unavoidably positioned close to the ground. In order to ensure that the propeller shaft has adequate ground clearance, it is necessary to divide the propeller shaft into a plurality of portions and connect them such that they are bent up and down. In addition, when assembling an entire powertrain, structured as a single unit, into the engine room from the front of or above the vehicle body, obstructions between the power output component of the propeller shaft of the powertrain unit and either a steering rack or a cross member of the body of the vehicle may occur. Such obstructions may hinder assembly.